The proposed project is designed to elucidate the mechanisms of ingestion, mastication and deglutition and their relation to cranial morphology in miniature pigs. The movements of oral structures (mandible, lips and cheeks, tongue, soft palate, hyoid apparatus) and of the bolus will be studied by cinematography and cineradiography. Patterns of muscular activity associated with these acts will be studied by surface and fine-wire electromyography. The highly complex and pinnate masticatory muscles will be explored for internal variation in function. After sacrifice these muscles will be examined histochemically for regional differences in proportions of physiologically significant fiber types. In addition to recording muscle activity during feeding, tooth contact and masticatory strain in various parts of the skull will be monitored. Age changes in the performance of feeding activities will be investigated.